Revert "Turn some compiler warnings into errors"

Do not turn some compiler warnings into errors by default. This patch
was added before --enable-werror was available.

We build with --enable-werror during development and in CI. If the code
is built with a different compiler that throws additional warnings, it
should not stop the build.

This reverts commit 34f012639ddf41470714ae74ae961d158670a4c7.

Related: OS#5289
Change-Id: Ideff462157a034e053e5e7049605dd8d24440905
1 file changed